The 741 op amp is one of the most famous and popular ICs with hundreds of millions sold since its invention in 1968 by famous IC designer Dave Fullagar. In this article, Ken Shirriff looks at the silicon die for the 741, discusses how it works, and explains how circuits are built from silicon.
I started with a 741 op amp that was packaged in a metal can (above). Cutting the top off with a hacksaw reveals the tiny silicon die (below), connected to the pins by fine wires.
Under a microscope, the details of the silicon chip are visible, as shown below. At first, the chip looks like an incomprehensible maze, but this article will show how transistors, resistors and capacitors are formed on the chip, and explain how they combine to make the op amp.